The present disclosure relates to microchips. More particularly, embodiments of the present disclosure relate to a microchip used in analyzing particles such as cells or the like.
Recently developed microchips are provided with regions or channels which are formed to perform a chemical or biological analysis on a substrate made of silicon, glass, or the like by employing micromachining techniques used in the semiconductor industry. Analysis systems using such microchips are called a micro-total-analysis system (micro-TAS), lab-on-a-chip, biochip or the like. These analysis systems are paid attention to as technology capable of enhancing the speed, efficiency, or integration of analysis, and further capable of providing a compact analyzing apparatus.
The micro-TAS is used in a case where an analysis is performed with small amount of samples or a case where microchips are designed for disposable use, thus the micro-TAS is particularly expected to be applied to a biological analysis which deals with valuable and very small amount of samples or a large number of specimens. As an application example of the micro-TAS, electrochemical detectors and compact-sized electrochemical sensors are presented. The electrochemical detectors are used in liquid chromatography, and the compact-sized electrochemical sensors are used in clinical or medical practice.
As another application example of the micro-TAS, there is a technology in which particles such as cells, micro-beads, and so on are analyzed in a channel provided on a microchip. In this technology, the characteristics of particles are analyzed in an optical, electrical or magnetic manner. In this particle analyzing technology, when there is a population (group) which is determined that a predetermined condition is satisfied according to the analyzed results, the population is separated and collected from among particles.
Patent Literature 1, for example, discloses “a microchip including a flow path through which liquid containing micro particle flows, an orifice through which the liquid flowing through the flow path is discharged to a space outside the chip, and a light-irradiated portion disposed in a predetermined location of the flow path for detecting an optical property of the micro particle”. The microchip disclosed in Patent Literature 1 is used to sort the micro particle determined to have a predetermined optical property by controlling movement directions of a liquid drop containing the micro particle discharged from the orifice.